One of the sure fire ways to increase breast milk supply is to feed the baby more. If the baby latches properly and sucks well then the lactational hormones are released. Bonding with your baby, spending more time with him without stressing about feeding also helps.
Ecospirin at a low dose is considered safe during breast feeding.
As for the quantity a baby would feed at 2 months, that's mostly decided by your baby. But a ballpark figure would be roughly around 150 to 170ml.